石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (2): 452-467.doi: 10.11743/ogg20230216

• 油气地质 • 上一篇    

泥页岩中有机质-黏土复合体的微观结构、变形作用及源-储意义

李晓霞1(), 谷渊涛1,2, 万泉3, 杨曙光3   

  1. 1.河南工程学院 环境与生物工程学院, 河南 郑州 451191
    2.南京大学 地理与海洋科学学院, 江苏 南京 210023
    3.中国科学院 地球化学研究所 矿床地球化学国家重点实验室, 贵州 贵阳 550081
  • 收稿日期:2022-08-02 修回日期:2022-12-20 出版日期:2023-04-01 发布日期:2023-03-17
  • 第一作者简介:李晓霞(1988—),女,博士、讲师,细粒沉积学。E?mail: lixiaox88@163.com
  • 基金项目:
    国家自然科学基金项目(41802143);河南省自然科学基金项目(212300410129);矿床地球化学国家重点实验室开放基金项目(201904);河南工程学院博士基金项目(DKJ 2018014)

Micro-architecture, deformation and source-reservoir significance of organic-clay composites in shale

Xiaoxia LI1(), Yuantao GU1,2, Quan WAN3, Shuguang YANG3   

  1. 1.School of Resources and Environment,Henan University of Engineering,Zhengzhou,Henan 451191,China
    2.School of Geography and Ocean Science,Nanjing University,Nanjing,Jiangsu 210023,China
    3.State Key Laboratory of Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550081,China
  • Received:2022-08-02 Revised:2022-12-20 Online:2023-04-01 Published:2023-03-17

摘要:

泥页岩中的有机质和黏土矿物在沉积演化过程中能够相互结合形成有机质-黏土复合体,成为重要的生烃母质。基于大量的场发射扫描电镜和透射电镜观察分析,以中国鄂尔多斯盆地三叠系延长组、黔北奥陶系-志留系五峰组-龙马溪组、黔中寒武系牛蹄塘组及南华北盆地二叠系山西组4套泥页岩储层为研究对象,详细查明了泥页岩中有机质-黏土复合体的微观结构及变形作用,并深入探讨了其源-储意义。泥页岩中有机质-黏土复合体成分复杂,形态多样,且易发生变形;驱动复合体发生变形的主要机制有构造应力作用、矿物颗粒作用、有机质赋存及黏土矿物转化。其中,由外部构造应力和复合体内部矿物颗粒对黏土层、有机质层挤压引起的变形能够改变复合体局部应力环境,所形成的拉张环境可使复合体发育大量纳米孔隙,且这些孔隙因黏土层的保护而不易发生烃类散失,可有效提升泥页岩的储集能力。相关结论有助于完善泥页岩的成岩理论,增进对页岩油气生成、运移和储集过程的认识,进而指导页岩油气的勘探开发。

关键词: 微观结构, 变形作用, 拉张环境, 储集能力, 有机质-黏土复合体, 泥页岩

Abstract:

The organic matter and clay minerals in shale can combine with each other to form organic-clay composites during sedimentation and evolution, which are an important source of parent materials of hydrocarbons. An integration of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) is applied to study the deformation and micro-architecture of organic-clay composites, and discuss their source-reservoir significance in depth. The object of study is the four suites of typical shale reservoirs, that is, the Triassic Yanchang Formation of the Ordos Basin, the Ordovician Wufeng-Silurian Longmaxi formations of northern Guizhou, the Cambrian Niutitang Formation of central Guizhou, as well as the Permian Shanxi Formation of the Southern North China Basin. The organic-clay composites in shale feature complex components, diverse geometries and being prone to deform, and the main mechanisms driving the deformation mainly include tectonic stress, mineral particles, the occurrence of organic matter and the transformation of clay minerals. The deformation caused by tectonic stress outside the composites and mineral particles (imposed on the surrounding clay layer and organic layer) inside the composites could change the local stress environment of the composites, resulting in extensional environment, which could in turn drive the large-scale development of nano-pores in the composites. Under the protection of clay layer, hydrocarbons stored in the nano-pores are less likely to loss, which could effectively improve the storage capacity of shale reservoir. The conclusions achieved in the study are of beneficial value to understanding the diagenetic evolution of shale, as well as the generation, migration and storage of shale oil and gas, thus guiding the exploration and development of shale oil and gas.

Key words: micro-architecture, deformation, extensional environment, storage capacity, organic-clay composite, shale

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